Mill and process for autogenous grinding of friable material

Claim 1

A ROTATABLE TUMBLING MILL FOR TREATING FRIABLE MATERIAL TO REDUCE THE SIZE THEREOF AND HAVING OPPOSED ENDS OF CONVEX CONFIGURATIONS SLOPING AWAY FROM EACH OTHER FROM THE PERIPHERY TO THE AXIS OF THE MILL, THE DIAMETER OF THE INTERNAL GRINDING ZONE OF THE MILL BEING SUBSTANTIALLY GREATER THAN THE AXIAL LENGTH THEREOF AND THE ENDS OF THE MILL BEING PROVIDED RESPECTIVELY WITH INLET AND EXIT MEANS, PERFORATED SCREENING MEANS CARRIED BY THE EXIT END OF THE MILL AND EXTENDING SUBSTANTIALLY RADIALLY INTO THE GRINDING ZONE OF THE MILL AWAY FROM THE EXIT MEANS ON SAID END, THE INNER SURFACE OF SAID SCREENING MEANS BEING EXPOSED TO THE MATERIAL UNDERGOING REDUCTION AND THE OUTER PERIPHERY OF SAID SCREENING MEANS BEING SPACED INWARDLY FROM THE OUTER PERIPHERY OF THE GRINDING ZONE OF THE MILL, AND DEFLECTING MEANS ADJACENT THE OUTER PERIPHERY OF SAID SCREENING MEANS HAVING A SUBSTANTIALLY ANNULAR DEFLECTING SURFACE EXTENDING ANGULARLY INWARD AWAY FROM THE EXIT END OF THE MILL CONTIGUOUS TO SAID SCREENING MEANS AND TOWARD THE AXIS OF ROTATION OF THE MILL, SAID ANNULAR DEFLECTING SURFACE BEING OPERABLE TO BE ENGAGED BY MATERIAL FALLING WITHIN THE MILL AND DEFLECT THE SAME AWAY FROM SAID SCREENING MEANS TO PROTECT THE SAME AND ALSO TO PRODUCE AN ADDED INTERMIXING ACTION UPON SAID MATERIAL WITHIN SAID GRINDING ZONE.